1. Field of Invention
This invention relates to pointing and control devices, especially to adjustable pointing and control devices.
2. Backgroound of the Invention—Prior Art
Pointing and control device serves as the interface between an operator and the equipment being controlled. The most popular pointing and control device is the computer mouse. A pointing and control device generally consists of a housing, a motion sensor, multiple controls, and an electronic circuitry that includes a microprocessor and a communication links (cable or wireless) to the computer or equipment. The most popular motion sensors include conventional roller-ball motion sensor, optical motion sensor, trackball, touch pad, and joystick. The motion sensor is either underneath (conventional roller ball and optical mouse) or on top (trackball, touch pad, and joystick) of the housing. It is responsible for generating two-dimensional (2-D) motion signals (including direction and amount) that are used by the computer to move the cursor on screen display. The controls are disposed on the exterior of the housing, and they include switch controls and roller-wheel controls. Each switch control is coupled to a micro-switch inside the housing, which is responsible for generating on and off control signals that are used to issue simple commands. Roller-wheel controls generate control signals that usually are used to control image scroll. The electronic circuitry processes the motion signals and control signals, formats them into suitable forms, and communicates them with the computer or equipment via the communication link.
To use a pointing and control device, a user places one (usually the dominant) hand on top of the device, uses fingers to operate the controls, and either slides it on a horizontal surface (a mouse-type) or uses fingers to operate the primary motion sensor (track ball, touch pad, joystick).
As computer window programs and graphical user interface (GUI) become increasingly popular, the use of pointing and control devices becomes more and more extensive and intensive. Intensive and prolonged use of pointing and control devices can cause repetitive stress injury (RSI) and copal tunnel syndrome (CTS) to the user's hand. It is believed that the most significant contributor to RSI and CTS is an incorrect hand posture. Most pointing devices require the palm plane of the users to be substantially horizontal, while the most comfortable (relaxed) palm position is at an angle roughly between 30 to 80 degrees from the horizontal position, depending on the individual and the working position. Awkward hand posture not only causes extra stress to relevant muscle groups but also makes the operation of the controls more difficult and stressful. Prolonged use of pointing and control device with incorrect posture results in fatigue, discomfort, and even permanent injury.
Many attempts have been made to solve this problem. The most popular approach, which represents the majority of the so-called ergonomic designs, is to move away from the symmetric design and make the top of the control device sloped to one side. For example, U.S. Pat. No. 6,091,403 to Bland (2000), U.S. Pat. No. 6,124,846 to Goldstein (2000), and U.S. Pat. No. 5,894,303 to Barr (1999) disclose such designs, where the user's palm plane forms an angle with the horizontal plane of approximately 20, 45, and 90 degrees, respectively. This approach suffers from a number of limitations:    1. It suits either right-handed or left-handed individuals, but not both. A right-hand design is extremely difficult, or even practically inoperable, for left-handed users, and vice versa.    2. It cannot provide the most comfortable operating position to all users even within the targeted handedness, since each person's most comfortable operating position differs from that of others.    3. It cannot provide the most comfortable operating position for the same user at all times, since the most comfortable operating position also depends on the user's working position.
U.S. Pat. No. 6,300,941 to Segalle et al. (2001), U.S. Pat. No. 6,229,527 to Sheam (2001), U.S. Pat. No. 5,731,807 to Feierbach (1998), and U.S. patent application Ser. No. 10/117,672 of Rodgers (2002) suggest using pliable materials for the top that can be molded to fit a user's hand. For such designs, composing the pliable materials with desired properties and designing the other parts (such as switch controls and wheels) in order to accommodate the moldable structure can be very difficult. Furthermore, such designs cannot provide the required mechanical integrity and stability, especially for accurate tasks such as graphics and CAD. In addition, the molded shape may gradually deform under the pressure of user's hand.
U.S. Pat. No. 5,847,696 to Itoh et al. (1998) and U.S. Pat. No. 5,260,696 to Maynard (1993) disclose movable caps on top of a pointing device, but the adjustment is limited to one direction and the switch controls do not move with the cap. U.S. Pat. No. 5,260,696 further has a v-shaped bottom, so that the device can be tilted to the left and right. But there is only one left and one right position, and the tilt angle is very limited, or significant motion encoding error (explained in that patent) may result.
U.S. Pat. No. 5,870,081 to Wu (1999) and U.S. Pat. No. 6,064,371 to Bunke (2000) disclose adjustable computer mouse housings, both based on a pivot mechanism, which allow the user to adjust the upper portion of the mouse. These designs suffer from a number of disadvantages:    1. The allowed adjustments of the upper portion are confined to a spherical surface centered at the pivot point, hence, the allowed adjustments are not independent (both pitch and roll adjustments are provided and thus correlated by the pivot shaft).    2. The allowed ranges of adjustments are limited, since they rely on open gaps between the upper and the lower portion, and an open-through hole (U.S. Pat. No. 5,870,081). Such open gaps and open-through hole are undesirable, since they allow dust and moisture to get into the housing. It is practically impossible for these designs to incorporate relatively large angle adjustments (for example, greater than 45 degrees).    3. The allowed ranges of adjustments also depend on the length of the pivot shaft, which in turn determines the height of the mouse, while a particular height may not fit all users or one user at all working positions.    4. The upper portion shifts horizontally away from the lower portion when tilted. This further limits the ranges of adjustments or the device may become mechanically unstable.    5. The allowed movement also includes the undesirable rotation of the upper portion about the pivot shaft axis, resulting in misalignment with the lower portion. This misalignment in turn causes an incongruent movement of the cursor relative to the movement of the mouse, which is undesirable, especially in delicate work such as graphics and CAD. Although U.S. Pat. No. 5,870,081 uses constraining bars and grooves to restrict such rotation, it cannot be completely eliminated, because, for the upper portion to be adjustable, some play between the constraining bars and grooves is required.    6. The range of the undesirable rotation increases with the ranges of desirable adjustments, since they all depend on the open gaps.    7. Since the adjustments rely on the gaps among the components, such designs require relatively strict dimensions and shapes of the parts, in order for them to fit each other, which increases the difficulty and cost in designing and manufacturing.
U.S. Pat. No. 6,154,196 to Fleck et al. (2000) discloses pointing device with an adjustable outer shell. The adjustment in this design also relies on the open gaps between the parts and a hole on the inner shell, hence having similar limitations and problems as U.S. Pat. Nos. 5,870,081 and 6,064,371. Furthermore, the adjustment is limited to only one direction at three stable positions (left, neutral, and right).
In addition to all the major disadvantages discussed above, the vast majority of the prior-art pointing and control devices having their controls configured for a targeted handedness (mostly the right-handed one), in the hardware. Although for computer pointing and control devices such control configuration can be switched by software, most people find the software switching cumbersome. In fact, many computer users, especially right-handed users, do not even know how to perform the software switching. This problem is significant for families with both left-handed and right-handed members, and public facilities such as computer centers, laboratories, and libraries. It is desirable that, especially for adjustable pointing and control devices that are supposed to accommodate left-handed and right-handed users, the control configuration can be easily shifted from one handedness to the other.
U.S. Pat. No. 6,362,811 to Edwards et al. (2002) discloses a computer mouse with button plate that can be detached, rotated by 180 degrees, and reattached to accommodate both left and right handed users. U.S. Pat. No. 6,373,468 to Leman (2002) discloses a computer mouse where the top cover has two sets of button caps and can be detached, rotated 180 degrees, and reattached. These detachable button plate and cover are inconvenient and hard to figure. U.S. Pat. No. 6,072,471 to Lo (2000) discloses a computer mouse with two sets of buttons, one for left-handed users and the other for right-handed users, with an external switch that allows a user to selectively disable one set of the buttons. A redundant set of buttons is clearly undesirable in many respects. Furthermore, users have to flip the switch to change handedness configuration. U.S. Pat. No. 5,841,425 to Zenz Sr. (1998) discloses a computer mouse with two sensors each for a handedness. This design requires a complex logic circuitry and a user must keep in contact with the sensor corresponding to the user's handedness and avoid touching the other sensor (for the opposite handedness), or otherwise the switch controls may not function. To avoid the inadvertent touch of the wrong sensor by other fingers or parts of hand, such sensors must be placed in secure locations. But then, a user has to make a conscious effort in order to keep in contact with the correct sensor. This requires additional awareness and effort on the part of the user, and it may cause further difficulty in more complex maneuvers, such as dragging an object and blocking (selecting) a portion of a document where a user has to perform three tasks simultaneously: keeping in contact with the correct sensor, holding down the let switch control, and moving the mouse. Furthermore, this system requires devotion of the user's thumb, hence, it may not be convenient to combine with other thumb-operable controls. U.S. Pat. No. 6,154,196 also mentions a sensor system that detects the user's handedness, and the computer (software) changes the switch control configuration accordingly. However, no detail of the sensor system is disclosed in that patent.